A person who investigates someone or something.
"The security examiner carefully searched every bag before allowing passengers through the gate."
In plain English: An examiner is someone who tests your knowledge by asking questions to see how much you know about a subject.
"The examiner asked me to show my identification before I could enter the testing room."
Usage: An examiner is typically an official, such as a teacher or inspector, who formally evaluates knowledge through tests or inspects items for compliance rather than conducting casual investigations like a detective would. Use this term specifically when the evaluation involves grading exams, checking credentials, or assessing condition in a professional setting.
The word examiner comes from the verb examine combined with the suffix -er to indicate a person who performs that action. It entered English as a straightforward formation meaning one who examines or inspects something.